1. Field of Technology
The present invention relates to an image processing apparatuses comprising a memory section constructed with a non-volatile hard disk and the like which memorize various data including image data, and having a function to carry out a synchronizing processing which transfers and memorizes the data of cache memory to the memory section based on a predetermined condition.
2. Description of Related Art
An image forming apparatuses such as a digital copying apparatus and a digital multifunction peripheral is required to control peripheral devices such as hard disk devices for storing large capacity image data and the like, network devices for sending and receiving image data and the like, and USB (Universal Serial Bus) devices, and therefore is generally equipped with an embedded operating system which supports a file system, and controls a whole system. The file system of the hard disk is mounted by “mount processing” which is executed at the time of start-up of the image forming apparatus, thereby the operating system becomes accessible to the file system.
In the above described image processing apparatus, the access speed of the hard disk is much slower than the operating speed of CPU (Central Processing Unit), therefore cache memory is arranged so as to increase the speed of the access to the hard disk device and thereby increase the processing speed of the whole system, and an asynchronous operation is executed in which the CPU generally writes data to the high speed accessible cache memory in stead of writing data direct to the hard disk device. Further in order to make synchronization (consistency of data) between the cache memory and the hard disk, a synchronous processing which transfers and writes asynchronous data (data in the cache memory which has not been written to the hard disk) from the cache memory to the hard disk is carried out at every predetermined interval or when an amount of the asynchronous data exceeds a predetermined threshold.
In a control shutting down a power of the image processing apparatus, when a main power switch is turned OFF by the operators or the power is shut down by a power failure, a firmware detects the falling down of the power supply by an interruption generated by detecting lowering of the supply voltage, the synchronous processing described above and “unmount processing” are executed while the firmware works by a secondary side output even after a primary side input has shut down, and thereby the data of the hard disk drive is protected.
However, in case when the amount of data to be synchronized is large, the processing time becomes long and may exceed the period to falling down of the secondary output. In some cases of built-in devices, the operable time of the secondary side circuit is prolonged by arranging a large capacity capacitor such as super capacitor at the secondary side circuit. Further, technologies enabling of continuing the operation of the secondary side circuit with a auxiliary power supply at the time of the power failure and the like, by arranging separately the auxiliary power supply such as an uninterruptible power source (for example, Japanese Patent Application No. 2000-357059) and a backup power supply (for example, Japanese Patent Application No. 2006-93963) are generally used.
However in the countermeasures of hardware using the auxiliary power supply or the super capacitor, a problem of increasing the cost of apparatus because of the high costs of the parts happens. In the case of the super capacitor, data of the hard disk drive may not be secured as the secondary side output is suspended during processing if the period of the synchronizing processing and the unmount processing extend more than expected unless a sufficient capacity is prepared. For example, when, during writing data to a super block which stores basic information of file system, the secondary side output is suspended and the writing terminates in the middle, errors of data of the super block occur. Therefore, at the worst case, the file system of the hard disk can not be recognized on the next start up and the image processing apparatus can not start up well.
One object of the present invention is to solve the above mentioned problems and supply an image processing apparatus, wherein an error of data to be memorized in the memory section is prevented on shutting down of the power supply and the prevention of the error of start up from the memory section can be realized with a simplified structure.